High Speed Driveline Vibration

Successfully took the truck on a 475 mile road trip recently without issue, except for developing a driveline vibration at high speeds. Here are the symptoms:

- No vibrations until 60mph
- Vibration felt from 60mph-70mph
- Vibration peaks at 65mph then disappears by 70mph
- Vibration seems to be magnified if I take my foot off the gas pedal and let it coast until it gets below 60mph then disappears.

I'm thinking either engine motor mounts or my rear driveshaft. Thoughts?

Check the easy stuff first
Tires...
One could have a belt separating,look for unusual wear on the tread,have someone slowly drive the truck while you watch the tread on each tire,look for a unusual bend in the tread.

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Originally Posted by Yukon6.2

Check the easy stuff first
Tires...
One could have a belt separating,look for unusual wear on the tread,have someone slowly drive the truck while you watch the tread on each tire,look for a unusual bend in the tread.

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I think I can cross that one off the list as these are brand new tires and wheels. The 475 miles of this trip were in fact 475 of the first 500 miles put on these tires.

That would actually increase my suspicion of a tire issue - either improperly balanced or a defect from the manufacturer.

You shouldn't cross tires off the list. Short of something blatantly obvious, tires should always be the first suspect. New or old. I've had many more issues with brand new tires than any with over a few thousand miles on them.

Quote:

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Originally Posted by trbankii

That would actually increase my suspicion of a tire issue - either improperly balanced or a defect from the manufacturer.

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Ok that makes sense. But if it was improperly balanced, wouldn't that show itself right away? I was 150-200 miles down the road before the vibration started. Wouldn't that lean more towards the manufacturer defect?

Hard to say. It could be a defect that appeared with some use - or it could be as simple as a balancing weight that wasn’t properly applied falling off.

With only ~500 miles on the tires, you should be in a good position with the tire shop. Have them check the balance, measure the roll-out (circumference, at the crown and shoulders) of each tire, and the tread-tracking (true tracking around the entire tire) while on the balancer. Also confirm the wheels are, in fact, round (it's surprising how often new wheels aren't, and steel are worse than aluminum). Any variation between the set indicates a bad tire. For over 20 years now, any set of LT (heavy duty, etc.) tires that goes on my trucks get checked for all of the above before any lug nuts get threaded. Larger tires have a greater chance of error, and I've had a few. Truck tires are expensive. They owe you that.

Quote:

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Originally Posted by DmaxMaverick

You shouldn't cross tires off the list. Short of something blatantly obvious, tires should always be the first suspect. New or old. I've had many more issues with brand new tires than any with over a few thousand miles on them.

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Ok, learning experience for me. I hadn't ever experienced issues with new tires before. I will investigate as prescribed by Yukon6.2!

Quote:

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Originally Posted by DmaxMaverick

With only ~500 miles on the tires, you should be in a good position with the tire shop. Have them check the balance, measure the roll-out (circumference, at the crown and shoulders) of each tire, and the tread-tracking (true tracking around the entire tire) while on the balancer. Also confirm the wheels are, in fact, round (it's surprising how often new wheels aren't, and steel are worse than aluminum). Any variation between the set indicates a bad tire. For over 20 years now, any set of LT (heavy duty, etc.) tires that goes on my trucks get checked for all of the above before any lug nuts get threaded. Larger tires have a greater chance of error, and I've had a few. Truck tires are expensive. They owe you that.

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Fortunately I picked up the tire warranty so if there's any issue I should be covered.

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Originally Posted by AugustDiesel

Fortunately I picked up the tire warranty so if there's any issue I should be covered.

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Tire warranties are OK, but with only ~500 miles, it shouldn't matter to you. The tire shop owes you the serviceable product you paid for. Unless they can show that you damaged them, they own the issue, and you shouldn't have to deal with any "warranty" process. Also note, tire warranties often have exclusions for 4x4 vehicle tires, stating they do not replace "pairs or sets" (and additional tire warranties are rarely carried by the tire manufacturer). This indicates they do, if fact, recognize the necessity for a matched set on a 4x4 vehicle, but will deny replacement of non-defect tires, regardless of that necessity. Several years ago, I had a new tire fail (B.F Goodrich, belt-shift). The tire shop happily replaced the failed tire, but refused to replace one other tire that was outside a maximum (2%, I think) roll-out difference. I appealed to the mfg, and they approved replacement of any tire in the set that wasn't within their recommended spec as a set installed on a 4x4 vehicle (I think ProComp has a similar recommendation, which becomes law, if it comes to that). I got 4 new tires. Major tire brand manufacturers stand behind their products. No manufacturing process is perfect, and I accept that. It was a lazy (crooked) tire shop that failed me.

Quote:

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Originally Posted by DmaxMaverick

Tire warranties are OK, but with only ~500 miles, it shouldn't matter to you. The tire shop owes you the serviceable product you paid for. Unless they can show that you damaged them, they own the issue, and you shouldn't have to deal with any "warranty" process. Also note, tire warranties often have exclusions for 4x4 vehicle tires, stating they do not replace "pairs or sets" (and additional tire warranties are rarely carried by the tire manufacturer). This indicates they do, if fact, recognize the necessity for a matched set on a 4x4 vehicle, but will deny replacement of non-defect tires, regardless of that necessity. Several years ago, I had a new tire fail (B.F Goodrich, belt-shift). The tire shop happily replaced the failed tire, but refused to replace one other tire that was outside a maximum (2%, I think) roll-out difference. I appealed to the mfg, and they approved replacement of any tire in the set that wasn't within their recommended spec as a set installed on a 4x4 vehicle (I think ProComp has a similar recommendation, which becomes law, if it comes to that). I got 4 new tires. Major tire brand manufacturers stand behind their products. No manufacturing process is perfect, and I accept that. It was a lazy (crooked) tire shop that failed me.

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Waiting for a callback from the shop (4 Wheel Parts) now. I may also have my driveshaft inspected while I'm at it.

Appointment scheduled for 7/29 to have them inspected.